The task of an extension device is to support the leg in a freely accessible manner in orthopedic surgeries such as, e.g., repositioning of bone fractures in the leg area or hip endoprostheses. To this end the patient's foot is received in a so-called extension shoe to the sole of which a feed rod unit is adapted. A tractive force can be applied via this feed rod unit in the longitudinal direction of the leg in order, for example to bring the broken edges of the bone into their original position during the repositioning, during which the leg should be able to pivot in and out.
An extension device of the initially cited type is known, for example, from the German utility model 20 2009 013 905 U1. In it, the patient support surface of an operation table is coupled to an orthopedic adapter that has interfaces for the coupling of an extension beam in the prolongation of the longitudinal beams of the patient support surface. To this end the extension beam has a coupling element with which it can be suspended on the interface parallel to the longitudinal direction of a longitudinal beam of the patient support surface. The coupling element has an articulation with a vertical articulation axis about which the extension beam can pivot in a horizontal plane. This solution has the disadvantage that the control element for locking the articulation in the immediate vicinity of the pelvic plate underneath it and in a hip operation therefore lies in the immediate operating area. This makes the control difficult when the patient's leg is to be pivoted during the operation.
Another solution is known from U.S. Pat. No. 4,940,218 A. This publication shows an orthopedic operating table with two permanently articulated extension beams that can pivot in a horizontal plane as well as in a vertical plane. The extension beams can not be separated.